At least one embodiment of the present invention generally relates to an electrical connector assembly having mateable contact pairs and more specifically, a connector assembly including predefined arcing zones located separate and apart from the final mating zones between blade and receptacle contacts.
In the past, ground and signal contact assemblies have been proposed that comprise pairs of mating receptacle and blade contacts. U.S. Pat. No. 5,116,230 generally describes a make-first-break-last connector assembly provided by making ground pins of a pin header longer than signal pins of the header in order that the ground pins engage ground contacts of a mating connector before the signal pins engage signal contacts thereof. U.S. Pat. No. 5,104,329 describes a connector assembly that uses ground plates, not ground pins, to afford a make-first-break-last connector assembly. U.S. Pat. No. 5,169,324 discloses an electrical connector assembly in which a connector mounted on a circuit board has signal contact springs for mating with complimentary contact elements of a mating connector similarly mounted on the circuit board. A planar grounding blade projects beyond the signal contact spring for mating with a grounding contact of the mating connector.
U.S. Pat. No. 5,582,519 discloses an alternative make-first-break-last connection. A pair of mating electrical ground contacts comprise a blade contact having a rearward blade support for retention in a first insulating housing and a contact blade projecting forwardly from the blade support, with a tab substantially narrower than the contact blade projecting forward from a forward edge of the contact blade. The pair of ground contacts comprises a receptacle contact having a rearward base for retention in an insolated housing and first and second contact springs projecting forwardly from the base. The first contact spring has a first transverse contact surface, while the second contact spring has a transverse contact surface that is substantially wider than the tab. The contact surfaces of the contact springs cooperate to apply contact forces to the tab and to the contact blade as the ground contacts are mated. The second contact spring defines a rearward opening for receiving the tab to allow full mating of the contact blade with the receptacle contact.
Connectors are being used in applications with higher and higher electrical performance demands, and thus improvement is needed to satisfy such demands. By way of example, today high performance connectors are in demand for applications such as telecommunications, computer systems requiring motherboard and daughter board connections, servers, networks, internet applications and the like. These applications use connectors having separable interfaces that may be connected and disconnected repeatedly while still affording high signal performance characteristics.
More recently, the power and signal requirements have been extended to new levels, such as for example, but not limited to, power connectors capable of carrying 50 volt DC power supplies at 30 amps per contact. In addition, signal contacts are needed to carry signals rated in different rating tiers, such as at or near 2.5 GHz (Tier 1), 5 GHz (Tier 2), 10 GHz (Tier 3), and the like. An improved electrical connector assembly is needed to satisfy the higher power and signal requirements of today""s applications.
In addition, connector assemblies are needed that better address the electrical phenomenon associated with xe2x80x9chot-pluggingxe2x80x9d or static electricity discharge. Hot-plugging refers to the process whereby the connector halves are mated while power continues to be applied to the board already mounted in the system. When cards or boards are added to the system while the power is on, arcing may occur. Another example is when circuit cards are stored before use, such cards collect static electricity. The collection of static electricity is not limited to motherboard and daughter card types of circuits. Instead, many other types of components and subassemblies have a tendency to collect static electricity during storage. The static electricity builds up in the component, card or subassembly until discharge to a ground. Typically these components are not grounded during storage, but instead are grounded for the first when inserted into a server, network, computer or other application. At the time that the card, component, subassembly and the like is inserted into a system, an electricity discharge may occur whether it be due to static electricity, hot-plugging or otherwise. In conventional connectors, the discharge occurs between the contacts at the mating interface where power or data signals are to be transferred to the card, component or subassembly once plugged into a server, network, computer and the like.
With today""s high electrical signal and power performance requirements of mateable connectors, the sensitivity of such connectors to electrical discharge is heightened. By way of example only, certain connectors may be coated at the mating interface with a material to facilitate the connection, such as gold plating and the like. However, the coating material becomes damaged and removed when arcing occurs since the coating material is not well suited to withstand the high voltage and/or current spikes that occur with hot-plugging or static electricity arc-type discharges. As the coating material degrades, the mating interface becomes susceptible to corrosion. As corrosion progresses, the resistance increases at the mating interface between the two connector halves of the contact assembly which in turn causes heating within the contacts. The chain of events (e.g., electrical discharge, corrosion, increased resistance and heating) induces an upper limit on the performance characteristics of the contact, such as by limiting the amount of power that the contact may handle and/or limiting the signal to noise characteristics maintainable by the contact for high data transmission speeds. In addition, as connectors are repeatedly unplugged and remated, the potential for additional build-up of a static electricity and discharge exists with each mating operation, thereby further exaggerating the foregoing problems.
A need remains for an improved connector that is capable of withstanding arcing in a manner that does not degrade the mating interface of the connector assembly.
An embodiment of the present invention is provided in which a pair of mating electrical contacts include a blade contact and a receptacle contact. The blade contact includes a support section that is securely mounted in an insulated connector housing and has at least one contact knife projecting from the support section. The receptacle contact has a base section that is securely mounted in an insulated receptacle housing and has at least one contact spring projecting from the base section. The blade and receptacle contacts are joined in a mating operation as the blade and receptacle contacts move from initial to final mating positions.
Blade and receptacle mating zones are defined on the blade and receptacle contacts, respectively. The mating zones electrically engage one another when the blade and receptacle contacts are moved to the final mating position to establish and maintain a primary electrical interface between the blade and receptacle contacts. Arcing zones are defined separate and distinct from the mating zones, with the arcing zones on the blade and receptacle contacts only being electrically engaged with one another when the blade and receptacle contacts are located in the initial mating position. The arcing zones provide a temporary electrical interface for discharging static electrical charge between the blade and receptacle contacts.
In accordance with one embodiment, raised dimples may be used on the blade and receptacle contacts to define signal and power interface regions and arcing regions located separate and remote from one another. The signal/power interface regions maintain the primary electrical interface, while the arcing regions provide temporary electrical interfaces. Alternatively, raised bumps may be used to define the blade and receptacle arcing zones. The bumps may be located on a sacrificial portion of an associated one of the blade and receptacle contacts remote from the primary electrical interface.
Alternatively, or in addition, multiple raised bumps may be used to define at least one of the blade and receptacle mating zones. The bumps may be located on a portion of an associated of the blade and receptacle contacts remote from areas that potentially experience arcing during a mating operation.
In accordance with at least one embodiment, the receptacle contacts are constructed with first and second contact springs projecting forward from a base section and cantilevered beams. The beams and springs define a gap there between to receive the knife contact. A crossbar is provided connecting outer ends of the first and second contact springs, with the crossbar including receptacle arcing zones thereon. Optionally, at least one of the first and second contact springs may also include a receptacle mating zone thereon.
Alternatively, a contact spring assembly may be provided that includes a proximal region near the base section constituting the receptacle mating zone and a distal region remote from the base section constituting the receptacle arcing zone. The distal region may come into contact with the blade contact during the mating operation when in the initial mating position, while the proximal region comes into contact with the blade contact during the mating operation only when in the final mating position.
As yet a further alternative, the receptacle contacts may be constructed in a U-shape with opposed spring legs projecting from a base section and joined with an interconnect at outer ends of the spring legs. The interconnect may include arcing zones, while the spring legs may include mating zones.
In accordance with one embodiment, an electrical contact assembly is provided that includes an insulated blade connector housing having a mating cavity in one end thereof and an insulated receptacle connector having a mating section adapted to be inserted into the mating cavity during a mating operation. A blade contact is securely mounted in the insulated connector housing and includes at least one contact arm extending into the mating cavity. A receptacle contact is securely mounted in an insulated receptacle housing and has at least one contact spring housed within the mating section. The blade and receptacle housings are joined in a mating operation in which the blade and receptacle contacts move from initial to final mating positions.
Mating interfaces on the blade and receptacle contacts are positioned to electrically engage one another when the blade and receptacle housings are moved to the final mating position. The mating interface is maintained at the primary electrical interface between the blade and receptacle contacts so long as in the final mating position. Arcing points are also provided on the blade and receptacle contacts and are located remote from the mating interfaces. The arcing points temporarily electrically communicate with one another only while the blade and receptacle connector housings are in the initial mating position to provide a temporary electrical interface affording an arcing point between the blade and receptacle contacts.